Fuel vaporizer carburetor



Se t. 20, 1966 c. MmozA 3,273,983

FUEL VAPORIZER CARBURETOR Filed Nov. 20, 1961 2 Sheets-Sheet 1 INVENTOR CLEME/VTE MIA 02A BY f ATTORNEYS Sept. 20, 1966 c. MlNozA 3,273,983

FUEL VAPORIZER CARBURETOR Filed Nov. 20, 1961 2 Sheets-Sheet 2 INVENTOR CLEME/V TE Ml/VOZA BY f ATTORNEYS United States Patent 3,273,l83 FUEL VAPURIZER CARBURETOR Clemente Mifioza, Diliman, Quezon City, Philippines, as-

signor of one-fifth to Felipe LL. Santillan, Quezon City, Philippines Filed Nov. 20, 1961, Ser. No. 154,107 Claims priority, application Republic of the Philippines, Jan. 27, 1961, 3,449 12 Claims. (Cl. 48-180) This invention relates in general to carburetion and fuel induction in internal combustion engines and more specifically to an improved and novel carburetor for vaporizing liquid fuels like kerosene, diesel oil, gasoline and alcohol; mixing the resulting fuel vapors with the proportioned amount of air; and finally feeding the metered combustible fuel-air mixture into the combustion chamber.

It is a common knowledge that the formation of a fuel-air mixture consists of vaporizing the fuel and mixing the finely divided particles of fuel with air. In conventional jet carburetors, vaporization of liquid fuel is accomplished by applying the liquid fuel through nozzles or jets into a stream of moving air. The induction stroke of the engine reduces the pressure in the cylinder and reduces the pressure gradient from atmospheric pressure to the lower pressure that exists in the carburetor, manifold and engine cylinder. This pressure drop causes the air to flow through the induction system and the fuel to be sprayed from the fuel nozzle or jet. The pressure drop at the exit of the fuel nozzle or jet is accentuated by a restricted or venturi section which increases the air velocity and pressured drop at this point. The fuel leaves the nozzle or jet more or less in a stream of droplets of various sizes. During this process, vaporization from the surfaces of the drop and particles takes place, causing the disappearance of the finest particles and the reduction in sizes of the others. The ideal situation would be to have all the particles vaporized and uniformly distributed before the mixture enters the engine cylinders. Since very little vaporization of the fuel occurs in the carburetor, further vaporization is usually obtained in the induction system of the engine. In this process even the most volatile fuel like gasoline is not completely vaporized, consequently, there is always liquid fuel in the form of fine mist present in the mixture as it enters the engine cylinder. This liquid fuel in the form of fine mist is the principal source of waste of fuel in the jet carburetor, since it cannot impart power to the engine because it only burns but does not explode.

The primary object of the present invention is to provide for a fuel vaporizer-carburetor which will completely vaporize the liquid fuel before being mixed with the air and fed to the engine cylinder.

Another object of this invention is to provide for a novel fuel vaporizercarburetor which preheats and completely vaporizes the liquid fuel into highly explosive vapors thereby effecting a complete combustion in the engine cylinder and a high thermal efficiency of the engine.

A further object of this invention is to provide for an efficient and effective fuel vaporizer-carburetor which is simpler in construction and operation and cheaper in cost of production than the conventional jet carburetors and fuel oil atomizers.

Still another object of this invention is to provide for a unique fuel vaporizer-carburetor which could efficiently replace the conventional jet carburetors for volatile fuels and the conventional diesel fuel atomizers and injectors.

Still another object of this invention is to provide for a unique fuel vaporizer-carburetor which would reduce the noise of the engine and thereby eliminate the use of the usual muffler or silencer.

Further objects, novel features of construction and arrangement of parts Will appear from the following description when read in the light of the accompanying drawings, wherein are disclosed a preferred embodiment of my invention.

According to the present invention a fuel vaporizen carburetor for use with an internal combustion engine, consists of an evaporator tube assembly heated by the engines exhaust gases and adapted to continuously vaporize the fuel supplied by a siphon from an auxiliary fuel tank, and to feed the resulting vapor into a mixer tube assembly which is connected to the inlet manifold of the engine and adapted to admit air and mix it in correct proportions with the vaporized fuel issuing from the evaporator tube assembly and allow a metered amount of the resulting fuel vapor and air mixture into the engine cylinder through the inlet manifold of the engine.

In carrying out the purpose of the present invention, briefly, the principle of operation is as follows: The liquid fuel in the auxiliary fuel tank flows through a siphon tube and drops on the upper end of a declining metal rod core which extends throughout the length of the evaporator tube and is Wrapped laterally around with metal sheet sleeve provided with holes at the upper portion. A stream of air flows at high speed through the holes at the lower portion of this evaporator tube, out of the said tube and then into the mixer tube at the suction stroke of the engine. This stream of air has a suction effect inside the evaporator tube. The combined action of gravity and the said stream of air forces the liquid fuel to flow through the holes at the upper portion of the metal sheet sleeve and down through the clearance between the inside surface of the evaporator tube and the outside surface of the metal sheet sleeve. The evaporator tube is being heated by the exhaust gases of the engine, which flow through the heat exchanger, so that when the liquid fuel comes in contact with the hot surface of the evaporator tube the fuel vaporizes, and flows in a vapor state into the mixer tube, where the vapor mixes with the air that flows through the holes in the baffle plate of the mixer tube. The fuel vapor and air mixture flows down the engine inlet manifold in metered amounts through the engine throttle valve.

In the accompanying drawings:

FIGURE 1 is the elevation of the whole fuel vaporizercarbu-retor assembly showing the relative locations of the different parts and indicating its position relative to the induction flow C-G and the exhaust flow A-B of the engine.

FIGURE 2 is the sectional view of the fuel vaporizercarburetor of FIGURE 1, showing the inside details of the different parts.

FIGURE 3 is a broken sectional View of the evaporator tube showing the relative position of the metal sheet sleeve and the metal rod core and showing also the position of the siphon tube with the needle valve, at the upper end of the evaporator tube.

FIGURE 4 is the elevation of the siphon tube with the needle valve, showing the attachment of the siphon tube to its flange, and

FIGURE is the sectional view of the upright mixer tube showing in detail the bafile plate with holes inside the mixer tube and how the lower end of the evaporator tube of FIGURE 3 is held in place.

In the following description reference numbers are used to indicate corresponding or similar parts in all of the views of the accompanying drawings and throughout the discussion, corresponding numerals refer to the same or similar parts.

In the preferred form of the invention as shown in the drawings, an auxiliary fuel tank 1, FIGS. 1 and 2, is connected to the fuel pump (not shown) of the engine. The level of the fuel in the tank 1 is kept constantly above the upper bend of the siphon tube 2 by means of a float valve (not shown). The fuel tank flange 7, FIGS. 2 and 3, is bolted (bolts not shown) to the evaporator tube flange 8, with gasket (not shown) in between the two flanges making the joint thereat airtight.

The siphon tube 2, FIGS. 2, 3 and 4, is a metal tube with small inside diameter, opened at both ends and bent in the form as shown in the drawings. This siphon tube 2 is fixed to the flange 5, FIGS. 2, 3 and 4. The evaporator tube flange 8 and the siphon tube flange 5 are bolted (bolts not shown) together so that the lower portion of the siphon tube 2, with the mouth 4 FIGS. 2, 3 and 4 is kept upright and the discharge end 6 of the siphon tube is kept in place in the axial hole of the metal rod core 9a inside the evaporator tube 10. In between the flange 8 and flange 5, a gasket (not shown) is placed to make the joint of the two flanges airtight.

The needle valve 3, FIGS. 2, 3 and 4, opens the siphon mouth 4, FIGS. 2, 3 and 4 which is always submerged under the liquid fuel, to allow the flow of the fuel through the siphon tube 2 when the engine is running and closes the same to stop the fuel flow when the engine is not operating. This needle valve 3 is always kept closed by means of a spring (not shown) when the engine is not running. The end of needle valve 3, outside the tank 1, as shown in FIGS. 1 and 2, is connected to one end of a lever (not shown) and the other end of the lever is connected by means of a chain (not shown) with a turnbuckle (not shown) to the plunger of a solenoid (not shown or an electromagnet (not shown). The fulcrum of the lever is between the two ends of the lever so that when the plunger (not shown) of the solenoid is pulled downward the needle valve 3 is lifted upward hence the siphon mouth 4 is opened. When the said plunger is released the needle valve 3 is pushed downward by the action of the spring (not shown) so that the siphon mouth 4 is closed. The purpose of the turnbuckle is to increase or decrease the tension on the chain (not shown) so as to vary the opening of the siphon mouth 4, FIGS. 2, 3 and 4. Increasing the tension on the said chain increases the opening of the siphon mouth 4, while decreasing the tension on the chain decreases the opening of the siphon mouth 4. Thus the amount of fuel flowing through the siphon tube 2 is controlled by the tension of the chain, because the said tension governs the opening of the siphon mouth 4. The opening of the siphon mouth 4 affects the fuel economy and the idling speed of the engine. If the opening of the siphon mouth 4 is too big, the idling speed of the engine will be high and not constant and the fuel economy of the engine will be low. The tension on the said chain should be adjusted by turning the turnbuckle clockwise or counter clockwise, until the idling speed of the engine is low and steady. When the proper idling speed of the engine is obtained the turnbuckle should not be turned any more so that the opening of the siphon mouth 4 will remain constant throughout the running operation of the engine. The coils of the electromagnet or solenoid are electrically connected to the battery of the engine with a switch in the connection. When the said switch is turned on, the solenoid is energized, its plunger pulls the said chain and lever thus the needle valve 3 is opened. When the switch is turned off the 4,. needle valve 3 will close by the action of the spring (not shown). This method of controlling the needle valve is a combination of electrical and mechanical means.

The needle valve can also be controlled by mechanical means alone. In the above mentioned method, the plunger of the electromagnet or solenoid may be replaced by a rod which could be pushed or pulled by the operator of the engine; pulling the rod opens the needle valve and pushing same closes it. Another method of controlling the needle valve is to use a device which operates like a pneumatic windshield wiper instead of the electro-magnet or solenoid. The needle valve, by means of a lever and chain with a turnbuckle is connected to the diaphragm of the pneumatic device which is connected to the suction manifold of the engine in such a way that when the engine is cranked or is running the needle valve is opened and when the engine is stopped the needle valve is closed by the action of the spring.

The evaporator tube 10, FIGS. 1, 2 and 3, opened at both ends and with a flange on the upper end is a metal tube of uniform inside diameter throughout its length. The lower end of the evaporator tube ltl is inserted into a hole at the side of the upright mixer tube 14, FIGS. 1, 2 and 5, in such a way that the evaporator tube is inclined with the horizontal as shown. The outside surface of the lower end of the evaporator tube 10 is welded to the mixer tube 14 so that the evaporator tube 10 and the mixer tube 14- are integral. At the lower portion of the evaporator tube 10 are primary air holes 13, FIGS. 1, 2 and 5. These primary air holes may be enclosed by an air tight casing (not shown) which may be connected by a tube to the air cleaner of the engine, so that the primary air passing through these air holes 13 will be clean. Near the middle portion of the evaporator tube 10 is the heat exchanger 12, FIGS. 1 and 2 Inside and extending throughout the length of the evaporator tube 10 is a metal rod core which is divided into two sections: the lower section 9 and upper section 9a, FIGS. 2 and 3. The entire length of said metal rod core is wrapped laterally around with metal sheet sleeve 11, FIGS. 2, 3 and 5, which has holes in its upper portion. The lower section 9 which is a solid rod is Wrapped tightly with the metal sheet sleeve 11, FIGS. 2, 3 and 5, so that the fuel will not be able to pass over the outside surface of the metal rod core 9 while the upper section 9a with an axial hole throughout its length fits loosely inside the upper portion of the metal sheet sleeve 11. There is a small clearance between the inside surface of the evaporator tube 10, and the outside surface of the metal sleeve 11 wherein the fuel will be able to pass. The discharge end 6 of the siphon tube 2, FIGS. 2 and 3, fits in the axial hole of the upper section 9a of the metal rod core. The fuel from the discharge end 6 of the siphon tube 2, FIGS. 2 and 3, will flow through the junction of the upper section 9a and lower section 9 of the metal rod core and out into the clearance space between the inside surface of the evaporator tube 10 and the outside surface of the metal sheet sleeve 11, through the holes in the upper portion of the metal sheet sleeve 11.

In order to heat the evaporator tube with the exhaust gases of the engine, the evaporator tube is provided with a heat exchanger 12, FIGS. 1 and 2, which is located at the middle portion of said evaporator tube 10. The main part of the heat exchanger is a short tube with its inside diameter bigger than the outside diameter of the evaporator tube. The evaporator tube passes through the inside of the short tube and the ends of the short tube are welded to the outside surface of the evaporator tube so that the joints thereat are airtight. The sides of this short tube are provided with two pipes opposite each other, marked A and B in FIGS. 1 and 2. Pipe A (partially shown) is connected from the exhaust manifold of the engine, while pipe B (also partly shown) leads to the atmosphere. The hot exhaust gases of the engine enter through A, FIGS. 1 and 2, surrounding that part of the evaporator tube 10 enclosed inside the short tube of the heat exchanger 12, imparting some heat thereto, and come out of B, hence the evaporator tube is heated. With this heat exchanger 12, FIGS. 1 and 2, the engine will run with very little noise or sound even without the usual muffler or silencer which can now be eliminated.

The mixer tube 14, FIGS. 1, 2 and 5 is a vertical tube of uniform inside diameter throughout its length. The lower end of the mixer tube 14 provided with flange is bolted to the upper flange of the adapter 17, FIGS. 1 and 2, while the lower flange of said adapter 17 is attached to the engine inlet manifold (not shown) so that the mixer tube 14 is kept upright. The upper end of said mixer tube 14 is connected to the air cleaner (not shown) of the engine. The lower portion of the evaporator tube FIGS. 1, 2 and 5 is inside the mixer tube 14, FIGS. 1, 2 and 5 as described in the previous paragraph. The baffle plate 15, FIGS. 2 and 5, which is a circular metal sheet, is welded to the inside surface in the upper portion of the mixer tube 14 as shown in FIGS. 2 and 5, above the lower end of the evaporator tube 10, FIGS. 2 and 5. The plane of the said baffle plate 15 is perpendicular to the vertical axis of the mixer tube 14, as shown. This baffle plate 15, divides the mixer tube 14 into two compartments, namely, the upper compartment D and the lower compartment E, FIGS. 2 and 5. The upper compartment D contains fresh air while the lower compartment E contains the mixture of fuel vapor and air. This baflie plate 15, FIGS. 2 and 5 is provided with venturi throat 16 and supplementary air holes 15a, FIGS. 2 and 5. The lower end of the high speed pipe 23, FIGS. 1, 2 and 5, is inside the venturi throat 16. One of these supplementary air holes 15a, is provided with a needle valve (not shown) so that the opening of this hole could be varied so as to valy the amount of fresh air flowing into the mixer tube 14. Another of the supplementary air holes 1542 may be provided with a flap valve (not shown) so that at high engine speed this flap valve will open to admit more fresh air into the mixer tube 14 in order to keep the fuel-air ratio more or less constant.

The adapter 17, FIGS. 1 and 2 is a tube of uniform inside diameter. The upper and lower ends of the said adapter are each provided with a flange. The upper flange is connected to the lower end of the mixer tube 14, FIGS. 1 and 2 while the lower flange is attached to the inlet manifold (not shown) of the engine. Inside the adapter 17, is a throttle valve 1 8, which controls the flow of the fuel-air mixture into the cylinder of the engine (not shown). The throttle valve 18 as shown in FIG. 2, which is a circular plate is set inside the adapter tube 17 such that its plane is inclined with the vertical axis of said adapter tube, when the engine is idling. The throttle valve 18 is attached to a spindle (not shown) which passes through the center of the said valve as a diametral axis thereof, so that the valve is opened or closed by turning the said spindle clockwise or counter clockwise. By means of a spring (not shown) connected to the spindle, the throttle valve 18 is always set in the position as shown in FIG. 2, when the engine is idling or at standstill. The spindle (not shown) which is perpendicular to the vertical axis of the mixer tube 14, is provided with a set screw so that the position of the throttle valve 18, for engine idling speed could be varied. To increase the valve opening, the valve 18, FIG. 2, is turned so that its lower edge will go down while its upper edge will go up. The valve 18, FIG. 2, is fully opened when it is in a vertical position. The lower end of the idling pipe 22, FIGS. 1, 2 and 5, extends into the inside surface of the adapter 17, at the airtight joint thereat as shown in FIG. 2. This adapter 17 may be also called the base of the carburetor.

The high speed pipe 23, FIGS. 1, 2 and 5, is a tube with small inside diameter. Its upper end connects with an airtight joint with the upper inner surface of the evaporator tube 10, near the middle portion thereof and inside the heat exchanger 12, FIGS. 1 and 2. The lower end of this high speed pipe 23 is in the venturi throat 16 as shown in FIGS. 2 and 5. This venturi throat 16 passes through the bafiie plate 15 as shown, so that the fuel vapor from the evaporator tube 10, FIGS. 1, 2 and 5, could pass through said high speed pipe 23, into the mixer tube 14 as shown, and then into the cylinder of the engine (not shown).

When the throttle valve 18, FIG. 2, is widely opened, the velocity of the air passing through the venturi throat 16, FIGS. 2 and 5 will be very high, thus, a low pressure is created at the lower end of the high speed pipe 23 at said venturi throat 16 so that the fuel vapor in the evaporator tube 10 will flow into the cylinder of the engine through the said high speed pipe 23. With this high speed pipe 23 which may be also called accelerating pipe, the engine will accelerate easily.

The idling pipe 22, shown in FIGS. 1, 2 and 5, is similarly a tube with small inside diameter. Its upper end is connected with an airtight joint with the lower inner surface of the evaporator tube 10, below the primary air holes 13 as shown in FIGS. 2 and 5. The lower end of this idling pipe 22 extends into the inside surface of the adapter 17, FIGS. 1 and 2, at the airtight joint 25 thereat as shown, slightly above the lower edge of throttle Valve 18 at its position shown in FIG. 2, set for idling speed of the engine. At this idling position of the throttle valve 18, there is small clearance between its lower edge and the inside surface of said adapter 17, FIGS. 1 and 2, thus the speed of the mixture of fuel va or and air passing through this small clearance is very high, so that the pressure at the lower end 25 of said idling pipe 22, FIGS. 1 and 2, will be very low, producing a suction effect thereat. The said idling pipe 22, helps to suck fuel from the evaporator tube 10, FIGS. 1, 2, 3 and 5, at the idling speed of the engine. The air passing through the air holes 13, FIGS. 1, 2 and 5, will also suck fuel from the siphon tube 2 into the evaporator tube 10, FIGS. 1, 2, 3 and 5.

Without this idling pipe 22, FIGS. 1, 2 and 5, at high engine speed, when the throttle valve 13, FIG. 2, is instantly closed up to idling position as shown, the engine will stop. The explanation is as follows. At high engine speed, the throttle valve 18, FIG. 2, is wide open. Air entering through the air holes 13, FIGS. 1, 2 and 5, together with the fuel vapor, will flow rapidly through the lower end of the evaporator tube 10, FIGS. 1, 2, 3 and 5, passing the throttle valve 18, FIG. 2, and into the cylinder of the engine (not shown). When the throttle valve 18 is instantly closed, the flow of air through the lower end of the evaporator tube 10 will be stopped, causing a rise of pressure in the evaporator tube 10 and hence the flow of fuel through the discharge end 6 of the siphon tube 2, FIGS. 2, 3 and 4, will be stopped so that the engine will also stop.

With this idling pipe 22, FIGS. 1 2 and 5, the engine will not stop when the throttle valve 18, FIG. 2, is instantly closed up to idling position, because when said throttle valve 18 is at idling position there is at once a suction effect in the idling pipe 22, so that the flow of fuel into the evaporator tube 10, FIGS. 2, 3 and 5 will not stop, hence the engine will continue to run. This most important function of said idling pipe 22, to prevent the engine from stopping when the throttle valve 18 is closed up to idling position is necessary because at this state, the high speed pipe 23, FIGS. 1, 2 and 5, has no more suction effect in the evaporator tube 10, because the speed of the air through the venturi throat 16, FIGS. 2 and 5, is very low.

This idling pipe 22, FIGS. 1, 2 and 5, may be provided with a needle valve (not shown) at its lower end 25, FIG. 2, thereat, in order to vary its opening so that the idling speed of the engine could be controlled.

The parts of the present invention are assembled and joined together as shown in FIGS. 1 and 2. It is necessary that all the joints, internal and external, are perfectly airtight. In a mobile engine, the present fuel vaporizer carburetor is preferably installed in such a way that the vertical plane containing the axes of the upright mixer tube 14, the inclined evaporator tube 10, and the siphon tube 2, as shown in FIG. 2, should be at right angles to the direction of motion of the vehicle. The auxiliary fuel tank 1, is connected to the discharge of the engine fuel pump (not shown). The inlet opening A of the heat exchanger 12 is connected by a pipe (not shown) to the outlet of the engine exhaust manifold (not shown) while opening B is connected by a pipe (not shown) that leads to the atmosphere. The upper opening C of the mixer tube 14 connects from the air cleaner (not shown) of the engine, and the lower flange G of adapter 17 is attached to the engine inlet manifold (not shown).

The detailed operation of the present invention is described as follows, explained in the light of FIG. 2. If gasoline is used, the starting tank 19, starting valve 20, pipe 21 and the fuel tank heater tube 24 (FIGS. 1 and 2) are not used. The fuel tank 1 is filled with gasoline up to a level above the upper bend of the siphon tube 2. The ignition switch (not shown) of the engine and the switch (not shown) of the needle valve 3, are turned on and with the needle valve 3 open, the engine is cranked. The gasoline will flow int-o the siphon tube 2 and out through the discharge end 6 since the fuel in the fuel tank 1 is higher than the discharge end 6. At the suction stroke of the piston (not shown) of the engine, air enters the primary air holes 13 and flows at high speed through the small clearance between the inside surface of the evaporator tube 10 and the outside surface of the metal sheet sleeve 11, into compartment E of the mixer tube 14. This air may be called primary air. This high speed primary air creates a partial vacuum in the evaporator tube 10, so that the gasoline in the evaporator tube 10 will partially vaporize. The fuel vapor passes through the high speed pipe 23, while the liquid fuel flows down through the clearance between the outside surface of the metal sheet sleeve 11 and the inside surface of the evaporator tube 10. The primary air licks the liquid fuel as it flows down the evaporator tube 10. This action of the primary air will vaporize the liquid fuel so that the primary air is charged with fuel va-por. This charged primary air flows from the evaporator tube 10, in a direction inclined with the horizontal and veers to a direction perpendicular to the horizontal. This change of direction makes the charged primary air turbulent. Fresh air from the air cleaner (not shown) of the engine, flows through the small supplementary air holes 15a, of the baffle plate 15 into the big compartment B, so that said fresh air will become turbulent. This turbulent fresh air, the charged primary air, and the fuel vapor from the high speed pipe 23 will mix homogeneously in compartment E to form an explosive mixture. This explosive mixture will flow into compartment F and out of the adapter 17 through opening G into the cylinder (not shown) of the engine. Then the mixture will explode in the cylinder of the engine and the engine will run. The hot exhaust gases of the engine entering the heat exchanger 12 through opening A, impart some of their heat to the evaporator tube 10. The evaporator tube 10 becomes hot, so that the fuel vaporizes when it comes in contact therewith. Some of the fuel vapor passes through the high speed pipe 23 and the rest flows down the evaporator tube.

Vaporization of the liquid fuel will be more or less complete, because a small amount of fuel at every suction stroke of the engine is under high temperature but at low pressure inside the evaporator tube. When the fuel is completely vaporized, the combustion inside the cylinder of the engine is nearly complete so that the exhaust gases of the engine will be more or less free from carbon monoxide and hydrocarbons.

When the hot exhaust gases of the engine are in the heat exchanger 12, they collide, come in contact with, and

impart heat to the surface of that portion of the evaporator tube 10 inside the heat exchanger 12. The exhaust gases coming out of the heat exchanger 12 will then be cooled and have low speed, hence, will not be noisy. Therefore with this heat exchanger 12, the usual muffler or silencer of the engine may be eliminated.

When the engine is idling, the throttle valve 18 is at the position shown in FIG. 2. The speed of the fuel-air mixture passing through the clearance between the lower edge of the throttle valve 18 and the inside surface of the adapter 17 will be very high. There is suction effect in the idling pipe 22, so that some of the fuel vapor flows through the said pipe, and the rest of the fuel vapor flows through the lower end of the evaporator tube 10. The fuel vapor will not flow through the high speed pipe 23, since there is very little suction effect in the said pipe because the speed of the air passing through the venturi throat 16 is very low. When the throttle valve 18 is opened a little wider, the amount of fresh air passing through the supplementary air holes 15a of the baffle plate 15 will increase. The speed of the air passing through the venturi throat 16 and through the primary air holes 13 will be very high so there will be a big suction effect inside the evaporator tube 10. The flow of fuel from the siphon tube 2 will increase and the amount of fuel-air mixture fed into the cylinder of the engine will increase; consequently, the engine speed will increase. But when the throttle valve 18 is opened too wide, the clearance between the lower edge of the throttle valve 18 and the inside surface of the adapter 17 will be very big, hence the speed of the fuel-air mixture passing through this said clearance will be very low so that there will be no more suction effect in the idling pipe 22. Thus the throttle valve 18 controls the speed of the engine and allows a richer fuel-air mixture during idling.

When heavy fuel like diesel oil is used, then the starting tank 19, starting valve 20, pipe 21 and the preheating tube 24 as shown in FIGS. 1 and 2, are used. The preheating tube 24 is connected by a tube (not shown) to the exhaust manifold (not shown) of the engine. This said tube 24 is like the tube of a fire tube boiler. The hot exhaust gases of the engine fiow inside the heating tube 24 while the fuel surrounds the outside surface so that the fuel in the auxiliary tank 1, FIGS. 1 and 2 is thereby preheated. The heat exchanger 12 and the tube (not shown) leading from the exhaust manifold (not shown) of the engine to the heat exchanger are all heat insulated when heavy fuel is used.

The starting tank 19 is filled with gasoline while the auxiliary fuel tank 1 is filled with diesel oil. The starting valve 20 is opened and gasoline will flow through the pipe 21 and into the evaporator tube 10. The needle valve 3 is closed so no diesel oil will flow into the evaporator tube 10. The engine is cranked and it will start and run for a while with gasoline as fuel, as discussed before. When the evaporator tube 10 and the auxiliary fuel tank 1 are hot, the needle valve 3 is opened and the starting valve 20 is closed. The engine will now continue to run with diesel oil as fuel.

It is believed that the advantages and features of the invention have been fully explained in connection with the above specification of the drawings and that those skilled in this art will understand the manner of construction of the invention and operation and use thereof. It is desired to point out that a considerable variation in many of the details may be made without in any way departing from the spirit or scope of the invention as defined in the appended claims.

What I claim is:

1. In a fuel carburetion system for internal combustion engines in which liquid fuel from a fuel feeder assembly is vaporized and mixed with air in a mixer tube assembly in predetermined ratios of air to fuel and said mixtures thereafter are introduced into the inlet manifold of the engine; in combination: an evaporator tube assembly disposed inclined and in communicating relation between the fuel feeder assembly and the mixer tube assembly, said evaporator tube assembly having an inlet and an outlet, said inlet in communication with said fuel feeder assembly to receive liquid fuel therefrom and said outlet being interior of said mixer tube assembly to discharge vaporized fuel therefrom, a heat exchanger assembly surrounding said evaporator tube between the inlet and outlet ends theerof, said heat exchanger assembly constructed and arranged for receiving exhaust gases from said engine for heating said evaporator tube, a first conduit means communicating between the interior of the heated evaporator tube and said mixer tube assembly, a second conduit means communicating between the interior of said evaporator tube assembly at a location ad jacent said heat exchanger assembly and said mixer tube assembly, means in the mixer assembly for selectively passing vaporized fuel through one or the other of said first and second conduit means into said mixer assembly, and air inlet means in communication with the inerior of said tube at a location between the second conduit means and the heat exchanger assembly whereby to permit introduction of air into the evaporator tube assembly during the operation of the engine.

2. The system as claimed in claim 1 in which said evaporator tube assembly comprises an elongate tubular member, a solid core member having an axial bore extending along a fraction of the length of said core and opening to one end thereof, said core member being disposed within said elongate tubular member, said core member having an axial passageway opening to the said inlet and a sleeve having a perforate portion adjacent one end thereof, said sleeve being arranged with the perforate portion loosely wrapped around that length of the core member coextensive with said axial passageway and the remainder of the sleeve tightly wrapped around the remain ing portion of said core member.

3. The system as claimed in claim 1 in which said mixer tube assembly comprises a hollow cylindrical vertically disposed member having a pair of coaxial compartments, said compartments being defined by a baffle plate and a venturi provided in said baffle plate, said first conduit means terminating in the venturi and said evaporator tube terminating interior of the lower one of said compartments.

4. The system as claimed in claim 3 in which said second conduit means terminates interior of said lower compartment and below the outlet of the evaporator tube.

'5. The system as claimed in claim -1 in which said fuel feeder assembly comprises an auxiliary fuel tank and a siphon tube having an entry and disposed interior of said tank and a dis-charge end disposed interior of said evaporator tube inlet, and needle valve means for said entry end.

6. In a fuel carburetor system for internal combustion engines and said system including fuel vaporizing means; a mixer tube assembly for mixing and feeding to the cylinders of said engines a selectively proportioned fuelair mixture, said mixer tube assembly comprising a vertically arranged tubular member having an air inlet at its upper end and outlet means for connecting said tube to the inlet manifold of the engine at the other end, baffle means disposed within said tube and spaced from the upper end thereof to define upper and lower chambers, said baflie means including a venturi throat and at least one air passage-way, first and second conduit means communicating between said venturi throat and fuel vaporizing means and between said lower chamber and said fuel vaporizing means respectively for introduction of said vaporized fuel into the respective chambers, and throttle means in said lower chamber for varying the internal pressure within said chamber to vary the passage of vaporized fuel through one or the other of said first and second conduit means.

7. In a fuel vaporizer carburetor of the type described, the combination comprising a fuel feeder assembly, an inclined evaporator tube assembly having upper and lower ends, the upper end being sealingly engaged with the fuel feeder assembly, and a vertically arranged mixer tube assembly, said lower end of said evaporator tube assembly terminating within said mixer tube assembly, heat exchanger means surrounding said evaporated tube assembly between the ends thereof and communicating with said engine to receive the exhaust gases there from, means to continuously feed fuel to and through said evaporator tube assembly to the engine in properly proportioned mixtures of air and fuel, said means comprising, a fuel feeder assembly including a liquid fuel reservoir and a siphon means communicating between said reservoir and said evaporator tube assembly to discharge a quantity of liquid fuel into the upper end of said evaporator tube assembly, vaporizing means within said evaporator tube assembly to vaporize said liquid fuel, and means for discharging said vaporized fuel into said mixer assembly, said last mentioned means comprising air inlet means provided in said evaporator tube assembly exterior of said mixer tube but closely adjacent the lower end of said evaporator tube assembly, and said mixer tube assembly being connected to the engine inlet manifold and comprising means for introducing additional air into said mixing tube assembly, plate means including a venturi throat for accelerating said additional air, a mixing chamber for proportionally mixing vaporized fuel with said additional air and throttle means for varying the pressure gradient in the mixing chamber whereby to meter a predetermined quantity of fuel-air mixture into the inlet manifold of the engine and further to operate said first mentioned means.

8. The combination as claimed in claim 7 in which said evaporator tube assembly includes an outer tubular shell member, an inner core member concentrically disposed therein, said shell and core members defining an elongate passageway extending the length of said members, said air inlet means formed in said outer shell member between the heat exchange means and the mixer tube.

9. The combination as claimed in claim 7 in which said evaporator tube assembly comprises an elongate hollow cylindrical member open at both ends, a concentric passageway interior of the tube and extending the length thereof, said first conduit means comprising an exterior accelerator pipe, one end thereof passing through said heat exchanger means to communicate with said passageway, the other end thereof communicating to the interior of the mixer assembly at the venturi throat.

10. The combination as claimed in claim. 7 in which said evaporator tube assembly comprises an elongate hollow cylindrical member open at both ends, a concentric passage-way interior of the tube and extending the length thereof, first conduit means comprising, an exterior accelerator pipe, one end thereof passing through the heat exchanger means and communicating with said passageway, the other end thereof communicating to the interior of the mixer assembly at the venturi throat for passing vaporized fuel from the heated portion of the evaporator tube into the mixer tube at the venturi throat, and a second conduit means comprising an idling pipe having one end thereof communicating with the lower port-ion of said cylindrical member and the opposite end thereof communicating with the said mixing chamber of said mixer tube assembly to provide an extra rich fuelair mixture when the engine is idling.

11. The combination as claimed in claim 7 in which said siphon means is provided with a valve for opening and closing same.

12. The combination as claimed in claim 8 in which said inner core is provided with an axial recess opening to the siphon means, and a sleeve disposed between said core and said tubular shell member, said sleeve being tightly engaged with said core along the length thereof 1 1 1 2 but loosely engaged with that portion of the core carry- FOREIGN PATENTS ing said recess.

878,382 9/1961 Great Bnt-aln. References Cited by the Examiner 349,054 1937 I ly UNITED STATES PATENTS 5 MORRIS O. WOLK, Primary Examiner.

1,950,806 3/1934 Mathes 123-133 X GEORGE MITCHELL Examme" 2,140,071 12/1938 Cleem 123-133 J. S. COVRONEK, Assistant Examiner. 

6. IN A FUEL CARBURETOR SYSTEM FOR INTERNAL COMBUSTION ENGINES AND SAID SYSTEM INCLUDING FUEL VAPORIZING MEANS; A MIXER TUBE ASSEMBLY FOR MIXING AND FEEDING TO THE CYLINDERS OF SAID ENGINES A SELECTIVELY PROPORTIONED FUELAIR MIXTURE, SAID MIXER TUBE ASSEMBLY COMPRISING A VERTICALLY ARRANGED TUBULAR MEMBER HAVING AN AIR INLET AT ITS UPPER END AND OUTLET MEANS FOR CONNECTING SAID TUBE TO THE MANIFOLD OF THE ENGINE AT THE OTHER END, BAFFLE MEANS DISPOSED WITHIN SAID TUBE AND SPACED FROM THE UPPER END THEREOF TO DEFINE UPPER AND LOWER CHAMBER SAID BAFFLE MEANS INCLUDING A VENTURI THROAT AND AT LEAST ONE AIR PASSAGEWAY, FIRST AND SECOND CONDUIT MEANS CONMUNICATING BETWEEN SAID VENTURI THROAT AND FUEL VAPORIZING MEANS AND BETWEEN SAID LOWER CHAMBER AND SAID FUEL VAPORIZING MEANS RESPECTIVELY FOR INTRODUCTION OF SAID 